package oo.ppt;

/**
 * @author DBX
 * @effect
 * @date 2021/09/05/10:45
 */
public class A {

    public String show(D obj) {
        return ("A and D");
    }

    public String show(A obj) {
        return ("A and A");
    }

}

class B extends A {

    public String show(B obj) {
        return ("B and B");
    }

    @Override
    public String show(A obj) {
        return ("B and A");
    }
}

class C extends B {

}

class D extends B {

}

